Characters Of Sphecid Wasps

Oxybelini are 10 mm. or less, stout-bodied, and dark-colored;

the propodeum bears a long spine, or forked process, and the base of the cubital vein in the front wing is weak or absent;

they nest in sandy areas and provision their nests with flies.

Bees: Superfamily Apoidea

Pronotum short, collarlike, with a rounded lobe on each side that does not reach tegulae. Body usually quite hairy, the body hairs branched or plumose. 1st segment of hind tarsi generally enlarged and flattened.

This is a large group, with more than 3300 N. American species; its members are to be found almost everywhere, particularly on flowers. Most species are solitary, nesting in the ground or in various natural cavities; the bumble bees and the Honey Bee are social. The cuckoo bees make no nest but lay their eggs in nests of other bees.

Bees are very valuable insects, largely because of the role they play in the pollination of plants; they are the most important insect pollinators. Insect-pollinated plants include most of our fruits, many vegetables, and important field crops such as clover, cotton, and tobacco.

Most pollen-collecting bees carry the pollen on their hind tibiae; the pollen-carrying surface of the tibia is usually bare and shiny and bordered with long hairs. Pollen sticks to the bee's body hairs when the bee visits a flower and is periodically combed off and placed on the hind tibiae. The 1st segment of the hind tarsi in most pollen-collecting bees is enlarged and flattened and bears a brush of hairs. Some bees do not have the hind legs so modified, and the leafcutting bees (Megachilidae) carry pollen on a brush of hairs on the ventral side of the abdomen.

The groups of bees are distinguished chiefly by characters of wings and tongue; the tongue characters are sometimes difficult to see, because the tongue when not in use is folded up tight against the ventral side of the head. The parts of the tongue in a large carpenter bee (Xylocopa) are shown opposite. To facilitate identification, the families of bees may be arranged in 3 groups:

1. Jugal lobe of HW as long as or longer than sub median cell; tongue (galeae and glossa) short; segments of labial palps usually similar and cylindrical; maxillary palps well developed: Colletidae, Andrenidae, and Halictidae.

2. Jugal lobe of HW shorter than submedian cell; tongue (galeae and glossa), labial palps, and maxillary palps as in Group 1: Melittidae (rare bees).

3. Jugal lobe of HW shorter than submedian cell, or lacking; tongue (galeae and glossa) long and usually slender; first 2 segments of labial palps long and flattened; maxillary palps well developed or vestigial: Megachilidae and Apidae.

marginal cell
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